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Search: id:A001260
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| A001260 |
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Number of permutations of length n by rises.
(Formerly M3999 N1657)
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+0
6
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| 1, 5, 45, 385, 3710, 38934, 444990, 5506710, 73422855, 1049946755, 16035550531, 260577696015, 4489954146860, 81781307674780, 1570201107355980, 31698434854748604, 671260973394676605, 14879618243581997745
(list; graph; listen)
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OFFSET
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5,2
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied Tables, Cambridge, 1966, p. 263.
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FORMULA
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(n-1)a(n)=(n+3)(a(n-1)n+a(n-2)n-a(n-1)+2a(n-2)).
E.g.f.: x^4/4!*exp(-x)/(1-x)^2. - Vladeta Jovovic (vladeta(AT)eunet.rs), Jan 03 2003
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MAPLE
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a:=n->sum((n+2)!*sum((-1)^k/k!/4!, j=1..n), k=0..n): seq(a(n), n=2..19); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 25 2007
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CROSSREFS
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Cf. A010027, A000255, A000166, A000274, A000313, A001261.
A diagonal in triangle A010027.
Sequence in context: A081070 A043025 A125836 this_sequence A088505 A067403 A022022
Adjacent sequences: A001257 A001258 A001259 this_sequence A001261 A001262 A001263
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Jan 03 2003
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